I am currently a student and have been using Esri software pretty much exclusively for my GIS needs. I occasionally use R for raster creation, especially as outputs of statistical models - which I usually bring back into Arc to work with.
I will be graduating in a year or so and may not continue to have access to ArcMap.
I am wondering what programs are recommended in the place of Arc. I currently use R for most of my raster work, but find that it can not always handle large rasters.
Of the other open source GIS software programs, is there one that has the most similarity to Arc (in capabilities and UI), or one (or some) that is easiest to learn coming from that background?
Is it common to use multiple programs for different functions, or do most people have only one or two programs they use?